i also have had this happen,2 times to be exact.,, in fact mine is in pieces sitting on my dresser . i had to both times take the gun down totally to get the cylinder out. as i think this is not an uncommon problem,,its still a pain in the rear. however since this is the second time its done it to me,,i figured i might as well do some tweaking on the parts while it was torn down. so i plan on polishing the hammer sides were its seated in the frame,,im thinking the problem lies in the cylinder paw,as i noticed mine was not as free,and smooth as i could make it.i figured it surely wouldnt hurt. i also noticed on the other side at the base of the trigger there is a small recesed pin.make sure it has a drop of oil on it.this i think contibutes to the problem. just my thoughts.